JPS605238Y2 - gas burner - Google Patents

Description

[Detailed description of the invention] The present invention relates to gas burners such as household gas appliances that supply combustion air at a relatively low pressure. The purpose is to provide a gas burner that can maintain combustion.

FIG. 1 is a system diagram of an embodiment of the present invention.

The burner body 1 is a plastic burner used in household gas appliances, and a fuel gas such as city gas is supplied through a fuel gas pipe 2, and combustion air is supplied from a blower 3 through an air pipe 4. at relatively low pressure (e.g. 50 m
mAq or less).

The fuel gas pipe line 2 is provided with a governor 5 for absorbing fluctuations in fuel gas supply pressure and a solenoid valve 6 for controlling the start and stop of fuel gas supply.

An orifice 7 serving as a pressure reducing means for reducing the pressure of the fuel gas is provided in the middle of the fuel gas pipe 2 on the side closer to the burner body 1 than the electromagnetic valve 6 .

The fuel gas pipe 2 is connected to the air pipe 4 via a conduit 8 closer to the burner body 1 than the orifice 7 .

A pressure equalizing valve 9 is provided between the orifice 7 of the fuel gas pipe 2 and the solenoid valve 6, and the upper chamber of the diaphragm of the pressure equalizing valve 9 is connected to the air pipe 4 on the upstream side of the connection position of the pipe 8. will be communicated to.

Therefore, the gas pressure P1 in the fuel gas pipe line 2 from the pressure equalizing valve 9 to the orifice 7 is kept equal to the air pressure P2 in the air pipe line 4.

Therefore, the pressure P3 in the fuel gas pipe 2 from the orifice 7 to the burner 1 is the air pressure P2 in the air pipe 4.
is kept below the value.

Therefore, part of the air supplied by the blower 3 is caused by the difference (P2-P3) between the pressure P2 in the air pipe 4 and the pressure P3 in the fuel gas pipe 2 after the orifice 7, as well as the pressure in the pipe 8. An amount determined by the pressure loss is introduced into the fuel gas line 2 via the line 8 as primary air.

The remaining air is blown out as secondary air from an air blowing hole (not shown) in the burner body 1.

By configuring as described above, the pressure of the fuel gas is controlled by the pressure equalizing valve 9 according to the blowing pressure of the blower 3.

Therefore, by setting the area of the air nozzle and the area of the gas nozzle (not shown) of the burner body 1 in advance, the amount of combustion air and the amount of fuel gas can be controlled proportionally, and the air-fuel ratio of the burner can be controlled in a proportional manner. is kept constant.

Moreover, the pressure P in the fuel gas pipe 2 up to the orifice 7
1 and the pressure P2 in the air pipe 4 are always kept equal, and the difference between the pressure P2 in the air pipe 4 and the pressure P3 in the fuel gas pipe 2 after the orifice 7 (P2 -P3)
varies in magnitude depending on the magnitude of the pressure P2 in the air pipe line 4.

Therefore, the amount of air (■3) introduced into the fuel gas conduit 2 via the conduit 8 is the amount of air (■1) flowing through the air conduit 4, which in turn is the amount of fuel gas (■2) supplied to the burner body 1. It changes almost proportionally.

Therefore, regardless of fluctuations in the amount of fuel gas, the proportion of the amount of primary air mixed into the fuel gas is kept approximately constant.

Therefore, combustion in the burner is stabilized over a wide range of combustion loads, and a large turndown ratio can be achieved.

Incidentally, as shown in FIG. 1, an orifice 10 may be provided in the middle of the conduit 8 to adjust the amount of primary air.

Further, instead of the orifice 7 as the pressure reducing means, a pressure reducing means such as a nozzle may be used.

Furthermore, the governor 5 shown in FIG. 1 may be omitted.

This is because the pressure P required to flow the maximum flow rate of fuel gas is
1, if a supply pressure greater than the pressure added to the pressure loss at the pressure equalization valve 9 at that time is secured, the pressure will be equalized so that it will be approximately the same value as pressure P1 or pressure P2 regardless of fluctuations in the fuel gas supply pressure. This is because the valve body of the pressure valve 9 moves up and down due to the diaphragm.

The results of experiments conducted by the inventor using manufactured gas are shown in Figure 2, and the results of experiments conducted using natural gas are shown in Figure 3.
As shown in the figure.

In both figures, the solid lines represent the total air volume ■1 and the fuel gas volume V2.
The dashed line shows the ratio V3/Vl between the primary air amount ■3 and the total air amount ■1, and the negative dashed line represents the total air amount ■1.

The production gas used in this experiment had Vl/V2 = 4 and the air-fuel ratio was 1, and natural gas had V1/V2 = 11.
．． 0 and the air-fuel ratio is 1.

In FIG. 2, V
The value of 1/■2 is approximately 5. It is kept constant in the vicinity, and V3
/Vl value is 6.0 to 10. It can be considered to be approximately constant within the range of OX 10-2.

In FIG. 3, for the total air amount ■1 which increases almost in proportion to the increase in pressure P2 in the air pipe 4, ■1/■
The value of 2 is kept constant near 14.0+f, and the value of V3
/Vl value is 7.0 to 10. It can be considered to be approximately constant within the range of Ox 10-2.

Therefore, regardless of the increase in the total air volume ■1, Vl/V2
Since the value of is almost constant, it can be seen that the air-fuel ratio is kept almost constant.

Furthermore, since the value of V3/Vl is approximately constant, it can be seen that negative air is mixed at a constant rate into the manufactured gas or natural gas, which increases in proportion to the increase in the total air amount (1).

As described above, according to the present invention, the pressure reducing means is provided in the middle of the fuel gas pipe, and the fuel gas pipe and the air pipe are communicated via the pipe downstream of the pressure reducing means, and the fuel gas pipe is connected to the air pipe through the pipe. A pressure equalizing valve is provided upstream of the pressure reducing means of the gas pipeline to control the secondary pressure to be equal to the air pressure according to the air output of the air pipeline upstream of the connection position of the pipeline. Since the fuel gas pressure is provided, the pressure of the fuel gas is proportionally controlled according to the air pressure, and therefore the air-fuel ratio can be kept constant.

In addition, primary air is mixed into the fuel gas at a substantially constant rate through the conduit, and accordingly stable combustion can be maintained over a wide range of combustion loads.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a graph showing the results of an experiment conducted using manufactured gas, and FIG. 3 is a graph showing the results of an experiment conducted using natural gas. 1... Burner body, 2... Fuel gas pipe, 3... Blower, 4... Air pipe, 7...・Orifice, 8... conduit,
9... Pressure equalization valve.

Claims (1)

[Scope of utility model registration request] The fuel gas pipe and the air pipe for supplying combustion air from the pneumatic supply source are individually connected to the burner body, and a pressure reducing means is provided in the middle of the fuel gas pipe to reduce the pressure. A fuel gas conduit and an air conduit are connected through a conduit downstream of the means, and air is connected to the fuel gas conduit upstream of the pressure reducing means and upstream of the connection position of the conduit. A gas burner characterized by being provided with a pressure equalizing valve that controls the secondary pressure to be equal to the air pressure in accordance with the air pressure in the utility pipe.